Probing Topological Superconductivity of oxide nanojunctions using fractional Shapiro steps

We theoretically discuss the emergence of fractional Shapiro steps in a Josephson junction created by confining a two-dimensional electron gas at an oxide interface. This phenomenon is induced by an alternating current of proper amplitude and frequency and can be tuned by a magnetic field applied perpendicular to the Rashba spin–orbit axis. The presence of fractional Shapiro steps can be associated with the creation of Majorana bound states at the boundaries of the superconducting leads. Our findings represent a route for the identification of topological superconductivity in non-centrosymmetric materials and confined systems in the presence of spin–orbit interaction, offering also new insights into recently explored frameworks. •Theoretical discussion on fractional Shapiro steps in Josephson junctions with 2DEG at oxide interfaces.•Fractional Shapiro steps induced by AC current and tunable via perpendicular magnetic field.•Link to the creation of Majorana bound states in superconducting leads.•Method for identifying topological superconductivity in non-centrosymmetric materials.•Demonstrated magnetic field dependence of half-integer Shapiro steps, relevant for topological phase detection.